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NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | STANDARDS | HISTORY | EXAMPLES | SEE ALSO | COLOPHON |
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UFFDIO_REGISTER(2const) UFFDIO_REGISTER(2const)
UFFDIO_REGISTER - register a memory address range with the
userfaultfd object
Standard C library (libc, -lc)
#include <linux/userfaultfd.h> /* Definition of UFFD* constants */
#include <sys/ioctl.h>
int ioctl(int fd, UFFDIO_REGISTER, struct uffdio_register *argp);
#include <linux/userfaultfd.h>
struct uffdio_range {
__u64 start; /* Start of range */
__u64 len; /* Length of range (bytes) */
};
struct uffdio_register {
struct uffdio_range range;
__u64 mode; /* Desired mode of operation (input) */
__u64 ioctls; /* Available ioctl()s (output) */
};
Register a memory address range with the userfaultfd object. The
pages in the range must be “compatible”. Please refer to the
list of register modes below for the compatible memory backends
for each mode.
The argp->range field defines a memory range starting at
argp->range.start and continuing for argp->range.len bytes that
should be handled by the userfaultfd.
The argp->mode field defines the mode of operation desired for
this memory region. The following values may be bitwise ORed to
set the userfaultfd mode for the specified range:
UFFDIO_REGISTER_MODE_MISSING
Track page faults on missing pages. Since Linux 4.3, only
private anonymous ranges are compatible. Since Linux
4.11, hugetlbfs and shared memory ranges are also
compatible.
UFFDIO_REGISTER_MODE_WP
Track page faults on write-protected pages. Since Linux
5.7, only private anonymous ranges are compatible.
UFFDIO_REGISTER_MODE_MINOR
Track minor page faults. Since Linux 5.13, only hugetlbfs
ranges are compatible. Since Linux 5.14, compatibility
with shmem ranges was added.
If the operation is successful, the kernel modifies the
argp->ioctls bit-mask field to indicate which ioctl(2) operations
are available for the specified range. This returned bit mask
can contain the following bits:
1 << _UFFDIO_COPY
The UFFDIO_COPY operation is supported.
1 << _UFFDIO_WAKE
The UFFDIO_WAKE operation is supported.
1 << _UFFDIO_WRITEPROTECT
The UFFDIO_WRITEPROTECT operation is supported.
1 << _UFFDIO_ZEROPAGE
The UFFDIO_ZEROPAGE operation is supported.
1 << _UFFDIO_CONTINUE
The UFFDIO_CONTINUE operation is supported.
1 << _UFFDIO_POISON
The UFFDIO_POISON operation is supported.
On success, 0 is returned. On error, -1 is returned and errno is
set to indicate the error.
EBUSY A mapping in the specified range is registered with
another userfaultfd object.
EFAULT argp refers to an address that is outside the calling
process's accessible address space.
EINVAL An invalid or unsupported bit was specified in the mode
field; or the mode field was zero.
EINVAL There is no mapping in the specified address range.
EINVAL range.start or range.len is not a multiple of the system
page size; or, range.len is zero; or these fields are
otherwise invalid.
EINVAL There as an incompatible mapping in the specified address
range.
Linux.
Linux 4.3.
See userfaultfd(2).
ioctl(2), ioctl_userfaultfd(2), UFFDIO_UNREGISTER(2const),
userfaultfd(2)
linux.git/Documentation/admin-guide/mm/userfaultfd.rst
This page is part of the man-pages (Linux kernel and C library
user-space interface documentation) project. Information about
the project can be found at
⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report
for this manual page, see
⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
This page was obtained from the tarball man-pages-6.9.1.tar.gz
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⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
2024-06-26. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-
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improvements to the information in this COLOPHON (which is not
part of the original manual page), send a mail to
man-pages@man7.org
Linux man-pages 6.9.1 2024-06-17 UFFDIO_REGISTER(2const)
Pages that refer to this page: ioctl_userfaultfd(2), UFFDIO_UNREGISTER(2const), UFFDIO_WAKE(2const)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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